The present invention generally relates to defect detection in semiconductor structures, and more specifically to post-lithography defect inspection using an e-beam inspection tool.
Lithography is utilized for the fabrication of semiconductor structures, such as integrated circuits and micromechanical structures. The basic process of producing a semiconductor structures involves the modification of the surface material of a semiconductor substrate, such as of silicon, in a pattern. The interplay of the material changes and the pattern defines the electrical characteristics of the microelectronic device. A similar process can be used to form micromechanical devices, by, for example, electroplating metal structures in a desired pattern onto a substrate. Lithography is used to define the pattern on the substrate, which will be doped, etched, or otherwise modified to form the microelectrical or micromechanical device.
In a basic lithography process for the fabrication of semiconductor structures, a photoresist is deposited on a substrate surface. The photoresist is sensitive to radiation, e.g., extreme ultraviolet (EUV) radiation, and, depending on the photoresist used, portions of the photoresist that are exposed to the radiation can be removed (or left remaining) by a development process. The semiconductor structure is formed by etching or otherwise modifying the substrate in the areas from which the photoresist has been removed. To form a desired pattern in the photoresist, the radiation that is used to expose the photoresist is passed through or reflected off of a lithography mask that defines the pattern that is to be transferred to the photoresist.